Protecting the privacy and confidentiality of data may be desirable and important for a company or an organization. However, sometimes the company or organization may need to make their sensitive data available to third parties. For example, during a financial audit, the company or organization may need to make their data available to a financial auditor. In this example scenario, two sets of privacy issues may need to be considered when a company's accounting data is audited by an external party. The company wants to safeguard its data, while the auditors want to safeguard their investigation methods.
Thus, multiple parties may have privacy and confidentiality concerns regarding their data and their methods. In the example provided above, the company wants to preserve the privacy of the data it lets the auditor access for the purpose of the audit. On the other hand, what makes the auditor effective and efficient in his work are the queries he runs, which are his know-how and intellectual property. The challenge is therefore to ensure both the privacy of the data and the privacy of the queries.